<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			//一、菱形
			document.write(" <center> ");
			var row=Number(prompt("输入行数"));
			for(var i=1;i<=2*row-1;i++){
			    var stars=2*row-1-2*Math.abs(i-row);//星星
			    for(var j=1;j<=stars;j++){
			        document.write(" * ");
			    }
			    document.write("<br>");
			}
			
			//二、1-100累加的和
			function recursion(i){
			  if(i==1)return i;
			  return i+recursion(i-1)
			}
			
			alert(recursion(100))
			
			
			
			</script>
	</body>
</html>
